1. Field of the Invention
The present invention relates to an ophthalmic apparatus for obtaining internal refractive power distribution of an eye, and a method for calculating the same.
2. Description of Related Art
Conventionally, an ophthalmic apparatus has been proposed which obtains internal (intraocular) refractive power distribution of an eye between a corneal posterior surface and a retina based on data on corneal refractive power distribution of the eye obtained by a corneal shape measurement apparatus or the like and data on whole refractive power distribution of the eye obtained by a wave front aberration measurement apparatus or an eye refractive power measurement apparatus, and displays the obtained internal refractive power distribution in a color-scaled map. With the use of this kind of apparatus, refractive power distribution of a crystalline lens, an intraocular lens implanted in the eye, and the like may be estimated. However, in the case of an eye with keratoconus and an eye having its axis deviated (decentered) at the time of corneal refractive surgery, the refractive power distribution of the crystalline lens cannot be estimated accurately since a corneal posterior surface as well as a corneal surface of the eye with keratoconus, and a corneal surface of the eye with the deviated axis are widely distorted, and thereby a prism component (component of tilt) is included in the internal refractive power distribution. Also in the case of an eye where the intraocular lens is implanted in a slanting position, the refractive power distribution of the intraocular lens cannot be estimated accurately since the prism component is included in the internal refractive power distribution.